[Bored chemist]

I asked ChatGPT again, Why Heat Capacity and Entropy Share the Same Units?

A real (educated) intelligence would tell you that you are mistaken.
They do not share the same units.

You should stop asking AI about stuff.

As an aside, I was chatting to a friend of mine who is doing a PhD in computer science and she pointed out that chat bots are not programmed to be accurate; they are programmed to "sound correct".
If you want your bots to pass a Turing test, you have to teach them to make the same dumb mistakes that people do.

Never rely on them for anything important.

[paul cotter]

Hi BC, I have repeatedly told him to forget these bots and pop-sci videos and obtain some good textbooks. Alas, this has been in vain and I predict confusion ad infinitum.

[hamdani yusuf (OP)]

They do not share the same units.

What's the difference between their respective units?

[hamdani yusuf (OP)]

Hi BC, I have repeatedly told him to forget these bots and pop-sci videos and obtain some good textbooks. Alas, this has been in vain and I predict confusion ad infinitum.

Which textbooks? What's their answer to my questions?

[hamdani yusuf (OP)]

As an aside, I was chatting to a friend of mine who is doing a PhD in computer science and she pointed out that chat bots are not programmed to be accurate; they are programmed to "sound correct".
If you want your bots to pass a Turing test, you have to teach them to make the same dumb mistakes that people do.

There are many models of chatbots. Some of them are even open sourced. New chatbots can be customized according to our needs.

[Bored chemist]

Formally they have the same units. J/K

Practically they don't, because (for heat capacity) you almost always add an amount so
J/K  mol or J/K Kg

But for entropy, the "unit" is often "per molecule/ atom " Those entities are countable, and a number is dimensionless.

On the other hand, "mole" is also a number.
It's a perennial problem in metrology. How do you measure "how much stuff you have".

If I make an apple and blackberry pie and I want it to be 50:50 apples and blackberries, do I mix a pound of apples with a pound of blackberries, or do I count out the same number of each?

You are left to figure it out from context.

[Bored chemist]

Hi BC, I have repeatedly told him to forget these bots and pop-sci videos and obtain some good textbooks. Alas, this has been in vain and I predict confusion ad infinitum.

Bots are cheap, easy and "convincing".
The fact that they don't believe there are three Rs in strawberry is, apparently, less important.

https://www.inc.com/kit-eaton/how-many-rs-in-strawberry-this-ai-cant-tell-you.html

That's not a problem because anyone can just count them and laugh at the stupid bot.
But it's a massive problem if you are trying to find the answer to something where you don't already know.
It's not really a new problem. Google, Lycos, AskJeves etc all screwed up royally in their early days. They got better but they are still not perfect.

[alancalverd]

Where you specify setting fire to things so we know that the temperature is much higher and there's a chemical reaction going on.

So, is " ΔT is proportional to ΔE" in that situation?

Up to the ignition point, yes. From there on, it's chemistry, not physics!

[alancalverd]

If I make an apple and blackberry pie and I want it to be 50:50 apples and blackberries, do I mix a pound of apples with a pound of blackberries, or do I count out the same number of each?

Old music hall joke:

I got rich selling chicken pies for ten cents

    How can you make a profit at that price?

I dilute the chicken with horse meat

     How much horse meat?

50/50. One horse, one chicken

[Bored chemist]

Where you specify setting fire to things so we know that the temperature is much higher and there's a chemical reaction going on.

So, is " ΔT is proportional to ΔE" in that situation?

Up to the ignition point, yes. From there on, it's chemistry, not physics!

The graphs I posted show that it's distinctly not constant up to "Fahrenheit 451".

[alancalverd]

But at 14.5 psi (say 1 bar) the variation between 0 (room too cold for comfort) and 200 Fahrenheit (fatally hot) appears to be negligible.

And HY's video seems to be about setting fire to paper, not air.

[paul cotter]

In engineering it is normal to differentiate between Cv and Cp, constant volume and constant pressure specific heats. But then i'm sure you all know this(well, mostly all).

[Bored chemist]

In engineering it is normal to differentiate between Cv and Cp, constant volume and constant pressure specific heats. But then i'm sure you all know this(well, mostly all).

Most of us do.
Some still seem to be struggling with the idea that you need air for a fire, and if it's cool enough the fire won't start.

[Bored chemist]

And HY's video seems to be about setting fire to paper, not air.

Oddly enough, so is  "Fahrenheit 451"- among other things.

[paul cotter]

A useless piece of information, fire without air or oxygen: chlorine trifluoride will set fire to glass wool.

[alancalverd]

Much confusion going on here.

In reply #900 I was discussing the temperature rise of the (paper?) target in the optical ignition video that HY posted. BC then threw in a graph of specific heat capacity of air over a huge range of temperatures and pressures, of dubious relevance  since the video clearly shows humans in a tolerable ambient. Once any water has evaporated from the target, the specific heat capacity of most common solids (including dry paper) doesn't change much until they melt or ignite.

[Bored chemist]

I'm sure we all look forward to Alan realising that, in order for the paper to burn in air, the air in contact with the paper also has to be hot.

Alan calls my post  " of dubious relevance" because it shows his was wrong.

AC
Thermodynamics tells us that  ΔT is proportional to ΔE, so what's the problem?
BC
What do you call the constant of proportionality?
AC
(Specific) heat capacity. Assuming no phase change, of course.
BC
So... this sort of "constant".
[graph of heat capacity being not constant]

[alancalverd]

in order for the paper to burn in air, the air in contact with the paper also has to be hot.

So no forest fires in Canada.

[Bored chemist]

in order for the paper to burn in air, the air in contact with the paper also has to be hot.

So no forest fires in Canada.

None which is started by air at 20 C.

Ever blown out a candle?

[alancalverd]

None which is started by air at 20 C.

Nor is the ignition of paper by photons. Air being virtually transparent to visible light, the air around the  paper will be a lot colder than 451F when the paper ignites.